Method and apparatus for bonding and debonding adhesive interface surfaces

ABSTRACT

The present invention relates to a system and a method of improving the debonding of two or more surfaces together. The invention utilises thermoexpanadable microspheres and thermal energy to debond interfaces in an adhesive system or as vehicle carriers. It also discloses a method of curing the adhesive system prior to the debonding step so that the same adhesive system may be used for both phases. It is especially useful in the automotive industry for end of vehicle life dismantling.

The present invention relates to a system and a method of improving theattaching or bonding of two or more surfaces together and a method ofdetaching or debonding them and an apparatus therefore. The method andapparatus of the invention is of particular, but not exclusive use, inthe automotive, aeronautical, nautical, decorating, packaging andconstruction industries for adhesive bonding and debonding adhesiveinterfaces of panels, frames, films, joints, plates, glazing or anyother such items which need to be bonded together and/or separated; insome instances the debonding system and method of the present inventionmay be applied to an adhesive. The present invention is also applicableto dentistry and surgery where it is desired to cement a dental fillingor in bone joint replacement. The system of the present invention mayalso use the thermally expandable microspheres as a vehicle ortransporter for other agents on their expanding shell surface and so aidin their dispersion within a matrix or other systems, including thecleaning industry or they may be used to disperse/mix multifunctionalparticles and/or nanoparticles so as to avoid clustering.

BACKGROUND TO THE INVENTION

It is known from the prior art to attach car body parts together, by forexample, riveting or spot welding them together and more recently laser.A recent trend in the car industry is to use a modular construction forvehicles, whereby individual modules are connected/attached/bonded toform the main vehicle body and associated parts. Typically car door orbody panels are welded and/or riveted together in order to achieve atight attachment of the two parts. Welding uses intense heat to melt oneor more of the interfaces of the parts and needs to be performed byspecialists aware of the risks of intense heat, both to themselves andto car parts. The intense heat can cause the substrate surface to buckleor melt and great skill is required to ensure that only thesections/portions/spots needing to be welded actually receive the heatso as to minimise the potential for heat damage to other parts. In orderto detach these riveted/welded parts strong mechanical strength isrequired.

It is also known in the prior art to use adhesive compositions to effectsecure attachment of two surfaces/substrates of vehicle components.Adhesive compositions or glues have been widely used to securewindscreens to frames by applying the adhesive to one or both surfacesof the components and aligning them so that the surfaces arebonded/attached together. Typically the adhesive compositions containcuring agents in order to promote or accelerate the adhesivesolidification process. The curing agents can be heat or moistureactivated and are included in the composition so as to cross-link orpolymerise the liquid adhesive into solid form and so accelerate thechemical bonding process. In order to detach the adhesive bondedcomponent(s) thermo-mechanical strength can be applied to separate them.For example, in the instance of detaching a windscreen from a framewhich has been firmly bonded in place as the adhesive sealant ishardened, typically involves the automotive glass fitter to remove thewindscreen (usually in intact form) using a device comprising acheese-wire or special knives to cut/saw through the hardened rubberalong the periphery of the windscreen. This process requires strongphysical force to separate structurally the cohesion strength ofadhesive and can lead to musculo-skeletal conditions in the fittersthemselves as a result of repetitive strain injury. Further problemsassociated with this method are that the cheese-wires can overheat dueto friction, additionally the wires themselves can break. It is becomingroutine in the automotive industry in an effort to minimise vehicleweight to improve performance and to reduce petrol consumption to employadhesives to bond other car components such as door skins to frames,accordingly the use of adhesive compositions is becoming more widespreadin this area of technology. In addition as the new End of Life Vehicle(ELV) Directive becomes implemented, there is a need for detachment ordebonding of adhesives in the automotive industry so as to dismantle andrecycle car parts such as bonded glazing, panels and so on in a quick,cost-effective, safe and if possible reusable way. Thus there is a needfor improvements to debonding various surfaces.

Thermally expandable thermoplastic microspheres have been commerciallyproduced for several years and have been used as fillers in polymers,paints, putty, plastisols, printing inks and as fillers in paper,paperboard and explosives. WO 95/24441 describes a substitute topolyurethane foams in the form of an adhesive composition for fillingvehicle box parts and providing sound-proofing which includes 5-15% ofexpandable micro-spheres encapsulating alkanes. WO 00/75254 alsodescribes adhesive and adhesive primer compositions comprisingthermo-expandable microspheres, heat activation of the microcapsulescreates a pressure along the interfaces of where the composition hasbeen applied which reduces the surface adhesive bonding and shear ortear stress of the adhesive material. The reduction in chemical and/orphysical bonding of the adhesion at the interface of the two bondedsurfaces is due to the effect of the expanded microspheres so that theymay be described as capable of de-bonding with no cohesive fracture whenin their expanded state. The microspheres present at the interfacechange the structure of the bonding adhesive surface to create instantdebonding when supplied with the appropriate trigger. The debondingsurface energy is approximately one third lower than the cohesivefracture energy.

One of the problems associated with the automotive industry is that atthe vehicle end of life (ELV) most of the vehicle components more than85% have to be detached and removed from the vehicle so that they can besafely disposed of or recycled in separate and dedicated processes. Thedisposal of vehicles at the end of life can be time consuming, hazardousto health and the environment and expensive as interior items,dashboards, panels, door skins, plates, frames, light units and othersuch components need to be detached from one another.

A method and apparatus to carry out a method which would enable rapid,ideally in a matter of minutes, non-toxic material degradation in anefficient manner and safe detachment of such components would offerimmediate advantage to the prior art, not only in the automotiveindustry but in any field where it is desired to detach twosurfaces/substrates that have been adhered (bonded together) by means ofan adhesive bonding system that can be present in either an adhesiveand/or primer and/oror cleaner component of the system.

It is envisaged that the method of the present invention may be used inmany diverse areas where microspheres are used, for example and withoutlimitation, in cleaning and hygiene, dentistry, surgical medicine,sports equipment manufacture, furniture and finishings especiallydecorative wallpaper and other situations where it is desired to detachmore than one surface. The increased volume of expanded microspheres mayalso be used to aid transport and dispersion of agents deposited ontheir surface so mitigating the problem of clustering and agentsresponsible for clustering a phenomenon associated with decreasedfunctional activity.

STATEMENT OF THE INVENTION

According to a first aspect of the invention there is provided a methodof debonding two or more surfaces or supports or layers of an adhesivesystem, the adhesive system comprising an adhesive composition at itsbonded surface(s), the composition being placed between said surfaces orsupports or layers, and the adhesive composition comprising an adhesiveagent and/or a primer and/or a cleaner at its interface and dispersedtherein thermoexpandable microspheres, in order to debond the system asufficient power level of thermal radiation and/or thermal energy isprovided which concentrates on the adhesive surfaces so as to expand themicrospheres in the adhesive and/or a primer and/or a cleaner layers andso causes weakening of adhesive surface forces at the interface of saidlayers in the adhesive system.

Preferably, the weakening of the adhesive forces at the interface ofsaid layers does not cause cohesive fracture or degradation of thematrix, especially toxic degradation of the matrix.

Preferably, the method further includes the step of curing the adhesivecomposition prior to debonding by providing a power level of thermalradiation and/ or thermal conduction and/or thermal energy which passesthrough the adhesive composition so the contents of the expandedmicrospheres leach or migrate through their porous shells into thematrix of the composition.

Preferably, the microspheres used in curing are uniformly distributed inthe adhesive matrix.

The present invention differs from the prior art in that the adhesivesystem comprising thermoexpandable microspheres at the cleaner and/orprimer interface is not directly heated rather the microspheresthemselves receive energy in the form of thermal radiation from an IR orUV source or electrical source and/or thermal conduction from thesurface of the item which is to be bonded. We have found surprisinglythat it is not necessary to heat the entire adhesive system/compositionas microspheres appear to preferentially absorb thermal radiation fromIR and that certain microspheres are able to expand at a lowertemperature than that of the composition. We have found that certainmicrospheres when exposed to IR energy expand at approximately 40° C.less than the adhesive in which they are mixed. In this way we haveunexpectedly found it is not necessary to heat the adhesive compositionin order to expand the microspheres but rather to heat the microspheresthemselves. Accordingly this provides the additional advantage ofminimising energy consumption and reducing the risk of damage to thebonded substrates.

Reference herein to an adhesive system is intended to include anadhesive composition comprising at least one adhesive agent with orwithout a primer and/or cleaner or curing agent or solvent or any othermaterial which is included to effect adhesion of one or more surfacestogether either as layers or sandwiches. The adhesive composition embedsor supports the microspheres and in the instance of the adhesive layerbeing comparable with the size of the microspheres both sides of theadhesive layer can be affected by the microspheres and triggered fromboth sides.

Reference herein to a cleaner and/or primer is intended to include anysurface treatment to promote the adhesion of adhesives and/or sealants.

The present invention provides a method and apparatus for debonding anadhesive system wherein the system comprises thermoexpandablemicrospheres dispersed in an adhesive composition the composition beingplaced between two or more surfaces of the system and optionally amethod of curing the same composition.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, or variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated integer or group of integers but not the exclusion of anyother integer or group of integers.

According to a second aspect of the invention there is provided anadhesive system comprising curing an adhesive composition and/orde-bonding the same adhesive composition at its bonded surface, thecomposition being placed between two or more surfaces of supports orlayers, and the adhesive composition comprising an adhesive and/or aprimer and/or a cleaner at its interface and dispersed thereinthermo-expandable microspheres the system comprising the steps of:

(i) activating a method of curing the composition by providing a firstpower level of thermal radiation and/ or thermal conduction and/orthermal energy which passes through the adhesive composition so thecontents of the expanded microspheres leach or migrate through theirporous shells into the matrix of the composition; and

(ii) de-bonding adhesive interfaces of the same surfaces of supports orlayers by providing a second power level of thermal radiation and/orthermal energy which concentrates on the adhesive surfaces so as toexpand the microspheres in the adhesive and/or a primer and/or a cleanerlayers and so causes weakening of adhesive surface forces at theinterface of said layers in the adhesive system.

Preferably, in the curing step the microspheres release their contentsuniformly into the adhesive matrix.

The method of the present invention thus may comprises two distinctphases or stages which not only are controllable but in practice areperformed at two different time points. It will also be appreciated thatthe adhesive system may use each of the distinct phases in isolation,that is to say it may only be used to debond an adhesive systemaccording to the first aspect of the invention or the may be performedwith the same adhesive composition so as to cure and debond the samesystem as in the second aspect of the invention.

The curing phase occurs subsequent or immediately after deposition ofthe adhesive composition and the debonding phase typically may beperformed days, weeks, months or years apart from the curing phase. Withthis in mind it is important that the microspheres used for curing areable to lay dormant, that is to say do not leach their contents into thecomposition matrix or in the stock before application; the debondingphase occurs in the cleaner and/or primer interfacing but not until themicrospheres are triggered so by application of thermal energyinstigated on command by a user.

The first phase or stage is curing; Curing is generated by a firstspecies of thermally expandable microspheres dispersed in the adhesivebead matrix. This first species encapsulates within their plastic orcopolymer shell a blowing agent and curing agent preferably mixedtogether and they may optionally further include a catalyst oractivator. The curing agent disperses in the adhesive matrix whensufficient thermal radiation and/or thermal conduction and/or thermalenergy and/or electrical energy is supplied to this first microspherespecies so as to cause their thermal expansion and allow their contentsto leach or migrate or pass or be transferred or released through oracross the porosity of the expanded shell. The contents of this firstspecies of thermally expandable microspheres is released into theadhesive matrix at a certain specified temperature which is typicallylower than that of the second species of thermally expandablemicrospheres which are employed to effect interface debonding. Thesecond species of microspheres, i.e. those which are activated at andifferent and typically elevated temperature to those of the firstspecies are preferably provided substantially as a blend in the cleanerand/or primer interfacing of adhesive compositions to facilitateseparation of the surfaces. Alternatively, the microspheres used indebonding can be provided as a blend in the adhesive itself, especiallyin adhesive systems requiring a low thickness or thin layer of adhesivecomposition comparable with the size of the microsphere in this way themicrospheres may be triggered from both interfaces of the layer.

It will be appreciated that the microspheres may be present dispersedthroughout an adhesive composition or they may be present in a primer orcleaning layer or in a paint layer so that when thermal energy issupplied to expand the microspheres they change the surface structure ofthe material in which they are dispersed so as to create an instantdebonding effect.

The present invention resides in providing energy in the form ofradiation and/ or thermal conduction and/or electrical heating to themicrospheres of either or both phases of the method of the first andsecond aspect of the invention. The thermal conduction and electricalheating to the microspheres for debonding is provided via contact withthe surface of the substrate or by electrical current or heat passingthrough the adhesive composition or system. It will be appreciated thatmicrowaves or supersonic waves may also be employed as a thermal source.

In the present specification, bonding refers to the physico-chemicalprocess of adhesion during the curing process and particularly thisbonding in the present specification is additionally increased bycreating an increased rough or uneven surface on the area of interfaceespecially by the thermoexpandable microspheres of the debondingmicrospheres in their initial state mixed in the cleaner and/or primer.Accordingly, the present invention advantageously is able to not onlyincrease the speed of curing but also to strengthen the adhesiveproperties of the composition at interfaces.

The debonding microspheres are suspended in the composition positionedor floating on the uppermost surface and with a suitable size theypurposefully create a rough or uneven increased surface area and thusprovide higher mechanical and stress strength as compared to an adhesivewithout microspheres.

Debonding refers to the physical breaking of the chemical formulation inthe adhesive system and breaking of the chemical bonding forces atinterfacings.

Expansion of the microspheres at the interface surface increases theirvolume so that the microspheres fill the entire surface space andsubstantially fill or occupy the whole interface surface, thus allowingfor the breaking of bonding forces at the interface or interface layers.

In the present specification, the curing process refers to a processseparate and distinct from the bonding and debonding processhereinbefore described. The purpose of the curing process is mainly toimpart mechanical structural strength to the adhesive composition andchemical bonding at an interface, it does not effect the volume of theadhesive bead rather it effects the mechanical behaviour of the bead andthe chemical bonding at the interface.

Preferably, inside the encapsulating shell of the first species ofmicrospheres used for curing, the curing activator may be mixed withblowing liquid and optionally a catalyst so that when activated bythermal energy the contents pass through the porous shell of theexpanded microspheres supported by the leaching of expanding gas. In thecase of an activator from the leaching of the blowing agent, theiraction of curing is distinguished from the process following uniformdistribution in the adhesive matrix. This may be achieved by UVradiation in the case of activators that are photo-radicals orphoto-ions, accordingly in this instance the activator leaching aids theuniformity of mix within the matrix.

Preferably, the expanding agent is selected from the group comprising anexpandable gas, a volatile agent, a sublimation agent, water, an agentwhich concentrates water or an explosive agent.

Preferably, the adhesive is polyurethane or polyvinylchloride or an MSpolymer or an epoxy resin or any other suitable adhesive in whichmicrospheres may be dispersed and which it is desired to strengthen orcure more rapidly. Thus, when the microspheres are used in dentalsituations the adhesive is a dental filling mixture and when used insurgical situations may be of a bone type cement.

Preferably the microspheres encapsulating the curing agent of the firstspecies of microspheres are activated at a different temperaturecompared to that of the second species, preferably the first speciesactivation temperature is lower that of the second species and thetemperature difference is between 20 to 100° C.

Preferably, the debonding or second species of microspheres areactivated in a temperature range of about 30 to 250° C. and morepreferably at about 110 to 200° C. Preferably the second set ofmicrospheres encapulate an expanding agent and are of smaller crosssectional diameter than the first species of microspheres.

It will be appreciated that in the first aspect of the invention onlythe second species of microspheres are required and optionally mayinclude the first species whereas in the second aspect of the inventionthe adhesive system comprises both species of microspheres.

In one embodiment of the invention where the microspheres are used inthe cleaning industry and especially as washing powder dispersing aidsthe temperature activation will be in the lower end of the range,probably in the region of 30 to 80° C., a temperature compatible withdomestic hot water.

In another embodiment of the invention where-the microspheres are usedin dental fillings the temperature activation range is in the region of40 to 70° C., a temperature compatible with oral conditions.

From the foregoing it will be appreciated that the temperatureactivation range is dependent on a users requirements and as such thetemperature activation of the microspheres is not intended to limit thescope of the application since it is the methodology of debonding at aninterface which is the essence of the invention and optionally curingbeforehand.

The shell of the microsphere is typically made of a copolymer acrylicand PMMA mix which has hitherto prevented their possible use belowaround 80° C. We propose to adapt the composition of the shell byincluding plastics such as polypropylene, PVC and/or polyethylene inthis way the microspheres may expand and much lower temperatures and sofind use with the method of the present invention in dental, medical andcleaning (washing powder) situations.

It will be appreciated that when using microspheres for both curing theadhesive and bonding/de-bonding microspheres at interfaces a sufficienttemperature difference is required so that the two processes may beachieved without overlap and thus distinct temperature ranges arepreferred. It will also be appreciated that the composition may alsocomprise thermoexpandable microspheres encapsulating more that onedifferent or combinations of agent and that each set or species ofmicrospheres may differentially be expanded when exposed to suitabletemperatures so that the composition may go through a set of definedprocesses according to the applied temperature which can be specified.Accordingly the method of the present invention is equally applicable tosticking and un-sticking, for example, wallpaper which will require alow thermal activation or it may be used to bond and de-bond vehicleparts which will require relatively higher thermal activation.

Preferably, the ratio of the proportion of the first species ofmicrospheres encapsulating the curing or other agent to those of thesecond species encapsulating the debonding agent will be variable and itwill be appreciated that the proportion may be selected according to auser's requirements or for the particular application in mind and thusshould not limit the scope of the application.

Preferably, the second species of microspheres may be coated in asuitable black or dark material to increase optical density and thusprevent UV light penetration to degrade the adhesive, in this embodimentthe “trigger” would be an IR or electrically generated thermal source.In one example when the method and composition is for use with vehicleglazing, the frit can be coated with microspheres coated with a darkmaterial with a purpose to further reduce penetration of UV light and toreduce degradation of the adhesive.

It will be appreciated that by coating the microspheres with a blackmaterial this acts to reduce the optical density of the frit on thewindscreen or, if desired, stereographical printing. We have found thatit is necessary to coat the microsphere in the appropriate material asthe coating affects their porosity. Thus when the microspheres expand,the porosity of the frit is affected and in practice, this creates abarrier to the UV. The expandable microspheres by virtue of the porosityof their spherical shell surface may be used advantageously to dispersenanoparticles and hence prevent or minimise clustering during mixing ofa dispersion composition which includes a curing plastic and a solvent.In this way, following evaporation of the solvent the microspheres mayact as a dispersant to avoid nanoparticle clusterization.

In this embodiment of the invention, that is to say coating of the shellof the microspheres with additional agents, the unexpanded microspheresmay be coated with agents depending on the user's requirements. Forexample the unexpanded microspheres may be coated with, for example andwithout limitation:

-   -   a monomer to be catalysed by UV radiation or other energies for        improved adhesion in a polymer matrix    -   nanoparticles to improve their distribution and/or their        dispersment.    -   molecules which create barriers to, for example, electromagnetic        waves, chemicals, O₂ degradation in the food packaging industry        so preventing premature spoiling, acoustic and sound waves,        thermal or any other function for which it is desired to create        a barrier.

These functions operate on the expanded surface which can realise up to10 m² for only 1 gram of microspheres present in the matrix. It isbelieved that the present invention may be used to improve thedispersment of, for example and without limitation, scent, fragrancesand/or cleaning agents into a solvent such as water. It may also be usedto improve the delivery of pharmaceuticals and other such agents. It mayalso be used as a barrier to prevent clustering of nanoparticles andsuch like. In addition nano-scavangers maybe used as a barrier to theatmosphere and so prevent food deterioration inside packaging film orpaper boxes/cartons.

In one embodiment of the invention, the shell of the microspheres can becoated with suitable molecules on their surface or they may encapsulatethem so that the microspheres act as a “vehicle” or “transporter” toenhance the effect of the carried molecule, and in so doing themicrospheres may improve efficiency and dispersion of the carriedmolecules. It is envisaged that the microspheres may, in thisembodiment, be used following the principles as set forth:

-   -   the microspheres may be used as a vehicle for dispersing a        carried molecule on its coating or which it encapsulates to a        larger molecule.    -   the microspheres may act as a chemical or physical barrier.    -   the microspheres prepare molecules to be evenly, easily and more        readily dispersed.    -   the microspheres can act as a support where photocatalysis is        efficient as the molecule acts as a very thin film on the        expanded microsphere surface.

In summary, the shell of the microspheres can be coated with orencapsulate various materials making them multifunctional and useful foraddressing many problems and of use in many different areas. Aspreviously stated the microspheres can be coated with or encapsulateeither a monomer and/or nanoparticles or a detergent or gold and theseentities can be distributed on the surface of the microspheres in theirunexpanded state and be multifunctional. We have utilised the change involume of the microspheres so that their surface becomes up to ten timesmore than their initial surface so one can achieve, from a single gramof microsphere in the matrix about 0.5 m² and if we use microspheres ofa different expansion capacity for example of up to 100 times the volumeexpanding we can achieve between 6 to 10 m² of surface. In such anembodiment, the microspheres can be used to disperse the parts of thematerials i.e. monomer and/or nanoparticles that are on their surface.In practice, we have found that clustering can be avoided when theunexpanded or initial microsphere shell is loaded with nanoparticles of20 nm diameter, in the expanded state where the nanoparticles remain onthe shell surface 76% distribution was achieved.

In this sense the microspheres act as a vehicle to make the coatedparticles ready to be dispersed in the salvage state in order to reducethe time of their dispersion and obtain a uniform distribution on theexpanded microsphere surface. Accordingly it is possible to achieve asurface that will attain the same longevity with the same particlesbecause the shell reduces thickness but the materials that are on thesurface of the expanded microspheres remain the same.

The microspheres may also be used according to a second criticalobservation in that they tend to become a barrier for electromagneticradiation and also a barrier to acoustic waves passing through such amatrix containing them. They may also be a barrier to atmosphericdegradation in the food packaging industry.

The microspheres may also be used to prevent clustering, that is to sayclumping together of molecules a problem associated with the cleaningindustry.

Preferably, the thermal radiation and/or thermal conduction orelectrical energy provided to the microspheres is provided from a meanscomprising a source of electromagnetic waves such as IR or UV radiation,or from a convection oven or from electrical means such as a battery ora laser or from an ultrasonic source or from gas or air or from whitelight.

In the instance of using the adhesive system as a backing in decorativepaper the debonding can be effected by for instance a domestic iron orhair dryer.

As will be appreciated IR is an electromagnetic wave which only becomesthermal when it is absorbed by a body with certain properties onto whichthe IR is directed. Thus a system employing IR only becomes a “thermal”system when the IR beam is absorbed by the body. Accordingly IRradiation becomes a heating source by changing the IR electromagneticwaves of 800-2600 nm up to thermal radiation 3000-7000 nm and thermalconduction. In the present invention the thermoexpandable microspheresare principally heated by IR or UV and/or thermal radiation and notthermal conduction from for example a metal panel.

In the instance of using IR radiation spectrum as the energy source, itwill be provided in the form of one or more lamps or in the form ofoptical fibres or optical rods or plates. IR radiation will betransformed to thermal radiation of the internal surface, of for examplea panel, on the heating side which strongly depends on the temperatureachieved by the panel exposed surface. The power thermal radiationdepends on the T exp 4 of the surface panels which is not within the lowrange of IR radiation as the lamp, but with thermal IR radiation ofabout 3000-7000 nm. It will be appreciated that heating by conductiondepends on many parameters such as the thermal conductivity of thematerial of the surfaces or panels, the cleaner-primer and thecomposition of adhesives layer.

In the instance of using an electrical heating as the heating source toexpand the microspheres, the electrical heating can be generated byelectrical current passing through a panel which becomes a resistor. Inone embodiment of the invention, aluminium or steelwires/filaments/strands or micro-wires or carbon microfibres or otherelectrically conductive fibres such as metal coated glass fibres areembedded in the adhesive composition especially at the adhesiveinterface so as to create a Faraday cage. The micro-wires are dispersedin the adhesive to create a tangle or polygonal arrangement ofelectrical conductors. This tangle allows a great number of smallelectrical rings to be formed in three dimensions all around theexpandable microspheres which can be caused to expand at a certainmaximum temperature. This phenomenon is referred to as tunnelling forelectrical current.

Preferably, the micro-wire or fibres are mixed with the adhesive and maybe around 100 μm in length and between 2-20 μm in diameter. In oneexample, carbon fibres could be 5-10 μm in diameter and 50-100 μm inlength. We believe that in order to effect tunnelling the compositionshould ideally comprise about 0.5-10% volume of the micro-wires and morepreferably about 1-3% volume. It will be appreciated that the volume %of microspheres within the composition affects the number of contactsbridging one with another and that this may be selected according to auser's requirements.

Preferably, the thermoexpandable microspheres may be provided embeddedor coated on to a tape or mesh or film or may be provided attached to awire or filament or fibre alternatively they may be attached to acontact surface of one or both component which it is desired to cureand/or separate. The first species of microspheres may be

Preferably, the released curing or activating agent is uniformlydistributed in the adhesive matrix so that they may be activated withtheir own energy system such as polymerisation and/or cross-linking orUV activation of photo-radicals and/or photo-ions.

Accordingly the present invention provides a unique approach to priorart methods of plastic-plastic, plastic-metal, metal-metal,ceramic-metal, aluminum-aluminium, aluminium-plastic, composite-metal,composite-plastic, composite-ceramic, paper-wall, dental-filling-tooth,artificial joint-bone and the like surface attachments since thecomposition is not directly targeted by for example an IR or UV beamtransparent to one of the sandwich panel but rather the composition isheated by thermal radiation and/or thermal conduction of the contactsurface or its under-surface.

Preferably, the method includes any one or more of the featureshereinbefore described.

In particular we have found by experimentation, investigating parametersof the IR lamp such as reflection, power and optical spectrum of theray's beam, that in order for IR to be absorbed by the blowing agent andits mixture it has to be adapted for expanding the microsphere at atemperature before the degradation of the matrix embedding themicrosphere or before the degradation of the adhesive system, where themicrospheres are embedded in the primer and/or cleaner interface. Inthis way, toxic agents, due to the degradation of the adhesive mayadvantageously be avoided even with PU adhesives.

According to a further aspect of the invention there is provided amethod of detaching two surfaces that have been bonded togethercomprising, supplying sufficient thermal radiation and/ or thermalconduction to a surface having coated thereon or attached thereto thecomposition as hereinbefore described, the thermal energy being suppliedto one or both contact surfaces of each item which are to bedetached/separated so as to cause a proportion of the thermoexpandablemicrospheres to release an expanding agent into the composition.

Preferably, the method includes any one or more of the featureshereinbefore described.

It will be apparent that in the present invention, chemical interactionsare avoided and that the method of the present invention relies onphysical engineering technology to permit and facilitate a curing systemwhich needs to mix the curing activator by a uniform distribution atcertain time at command in the adhesive bonding stage process andadvantageously may also differentiate zones where the thermoexpandablemicrospheres can be suitably mixed. In principle the thermoexpandablemicrospheres act as microscopic containers of the curing activatorswhich are neutral or inert up to a certain moment when they break orincrease their volume in such a way to initiate their shell as a porouswall to leach the activator, in gas or liquid state, so that it candiffuse uniformly in to the adhesive matrix transport by the gas ofblowing agent.

Activation of different activators is possible by the differentiation oftemperature activation for the thermoexpandable microspheres, in thisway it is possible to effect curing of the adhesive composition atdifferent stages in the process at different areas and moreover atapplied and specific commands making the overall process morecontrollable and with multifunctional performances.

The present invention advantageously provides a curing process that iscontrollable in that it is not dependent on a chemical reaction such aspolymerisation, cross-linking, crystallisation, gelification or anyother phase transitions.

According to a yet further aspect of the invention there is provided anapparatus for attaching or detaching two surfaces that have been bondedtogether comprising an IR emitting device comprising at least one bulb,at least one lens to concentrate the beam at certain area and at leastone reflecting mirror mutually arranged so that heat is directed orfocused only at an adhesive interface or an adhesive interface with acleaner and/or primer or a path where the thermoexpandable microspheresare purposely present.

In one embodiment of the invention the IR emitting device is in the formof one or more lamps and typically is in the form of a group orplurality of lamps.

Preferably, the IR device emits IR radiation in the range of about800-1400 nm to 2000-6000 nm.

Preferably, the device is automated and may be linked to a computerprogramme providing information to device sensors of an adhesivebonding-path.

Preferably, the device is mounted on a mobile unit so that it is free tofollow a predefined adhesive bonding path.

The arrangement of the device of the present invention allows the IRbeam to be concentrated only at certain partial points of the surfacewhich it is desired to bond or de-bond.

Preferably, lenses with parallel shape of the adhesive-thermoexpandablemicrosphere, bonded paths can be used with standard IR lamps where thebeam can be concentrated in a special area. In this heating concept theIR optical fibre or optical tubes, even with the laser source, can beused as a flexible or rigid heating tool producing strong and rapidpower by rapidly moving along the bonded area with special designeddrawings of adhesive parts.

Preferably, the device may be pre-programmed to follow a specificbonding path.

According to a yet further aspect of the invention there is provided amethod of de-bonding an adhesive composition, the composition beingpresent at an interface and being placed between two or more surfaces ofvehicle glazing or vehicle panel(s) or part(s) the compositioncomprising an adhesive or cleaner and/or primer and thermoexpandablemicrospheres dispersed therein the microspheres having a diameter ofbetween 10-50 μm and an activation temperature range of between 110-210°C. and encapsulating at least one blowing agent the debonding beingeffected by exposing the microspheres power level of thermal radiationand/or thermal energy that results in a temperature received by themicrospheres in the range of 110-210° C.

Preferably, the method further includes the step of curing the adhesivecomposition prior to debonding by providing microspheres 30-50 μm and anactivation temperature range of between 50-100° C. the microspheresencapsulating a curing agent and/or catalyst and/or activator andeffecting curing by exposing the microspheres power level of thermalradiation and/or thermal energy that results in a temperature receivedby the microspheres in the range of 50-100° C.

According to a yet further aspect of the invention there is provided amethod of curing an adhesive and de-bonding the same adhesive fromautomotive glazing or panels or parts comprising applying a compositioncomprising an adhesive and thermoexpandable microspheres dispersedtherein, a first set of microspheres having a diameter of between 30-50μm and an activation temperature range of between 50-100° C. and asecond set of microspheres having a diameter of between 10-50 μm and anactivation temperature range of between 110-210° C. the second set ofmicrospheres being present at an interface of the adhesive or cleanerand/or primer, the composition being placed between two or more surfacesof the glazing or panel or part(s) and:

(i) activating curing of the composition by exposing it to a first powerlevel of thermal radiation and/or thermal energy that results in atemperature received by the microspheres in the range of 50-100° C.; and

(ii) de-bonding the adhesive system at its interfaces by exposing it toa first power level of thermal radiation and/or thermal energy thatresults in a temperature received by the microspheres in the range of110-210° C.

As mentioned herein before the steps of curing and debonding may beperformed in isolation with the same composition or may be debonded withor without a curing phase, the requirement for a curing step is notintended to limit the scope of the application.

The system in step (i) activates curing of the adhesive composition, byexposing them to a first level power of thermal radiation and/or thermalconduction or a thermal energy. This thermal energy passes through theadhesive system to the microspheres; so the contents of the expandedmicrospheres leach or migrate through the porosity of the microspheresshell. The shell thickness is reduced due to its expanded state. Itscontents leaches or migrate into the matrix of the adhesive compositionthus releasing a curing agent or catalyst or activator, into the matrix.This process occurs subsequent to adhesive deposition on the glass orplates.

The system in step (ii) debonds adhesive interfaces of the same glazingor panel or part treated with the method (i), by exposing them to asecond power level of thermal radiation and/or thermal conduction andthermal electrical energy. This second power level activates themicrospheres so they expand and so weaken and/or debond the surfaceadhesive system forces at temperature advantageously lower than thedegrading temperature of the adhesive system composition.

It will be appreciated that step (i) may occur just after the beadadhesive deposition and trigger the microspheres expansion to generatethe leaching of the blowing glass containing the catalysts of theadhesive matrix to a curing process; step (ii) may occur after 10 to 15years. This second step may be trigger the dormant microspheres byexposing the adhesive surfaces to a second power level energy by IR orelectrical systems generating thermal energy.

The present invention provides an elegant method for curing anddebonding of the same adhesive. Bach stage being a discrete operationthat may be performed up to 10 years or more apart since themicrospheres are able to lay dormant in the composition until triggeredat command by an appropriate stimulus for example IR or electricallygenerated thermal energy.

The invention will now be described by way of example only withreference to the following Figures wherein:

FIG. 1A shows an electron microscope picture of an upper surface of aninterface to be bonded;

FIG. 1B shows an electron microscope picture of a tangle of micro-wiresand thermoexpandable microspheres;

FIG. 1C shows a higher power view of FIG. 1B and a micro-wires;

FIG. 1D shows an alternative view of FIG. 1C and a micro-wire;

FIG. 2 shows a schematic plan view of a microcapsule and filmarrangement; and

FIG. 3 shows a front perspective view of a vehicle doorframe and skinwith a conductive pathway in situ.

FIG. 4 shows a plurality of possible interfaces in the adhesive systemof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1A there is shown an electron microscope pictureof the surface of a primer adhesive interface coated with thecomposition and microspheres according to the present invention;Microspheres 1 can be seen projecting above the surface thus providingan uneven or rough surface. There are gaps between the microspheres.However these gaps or voids are filled once the microspheres have beenexpanded so that the surface will become more even and thus be able tobe debonded. In FIG. 1B there is shown an electron microscope picture ofa tangle of micro-wires and inter-dispersed microspheres are alsovisible. As described earlier aluminium or steelwires/filaments/strands, carbon microfibres, metal coated glass fibresor micro-wires are embedded in the adhesive composition especially atthe adhesive interface so as to create a Faraday cage. The micro-wiresare dispersed in the adhesive to create a tangle of electricalconductors. This tangle allows a great number of small electrical ringsto be formed in three dimensions all around the microspheres which canbe caused to expand at a maximum temperature. FIGS. 1C and 1D areelectron microscope figures at higher powers of magnification.

In one embodiment of the invention, the microspheres (1) and micro-wires(2) can be attached to a continuous conductive filament or film or wireor fibre (4). Energy is supplied to the conductive filament (2) from anenergy source (3), the energy source may be provided in the form ofthermal energy or electrical power and transmitted to the microcapsulesby thermal radiation and/or thermal conduction. Thus the microcapsule donot receive energy directly from the energy source but rather via thepanel or component surface which is to be bonded, for example themicrospheres may be heated by thermal radiation and/or thermalconduction of the panel, directly targeted by an IR radiation lampfocused on the open/exposed surface. In a yet further embodiment of theinvention microcapsules (1) may be coated on to a mesh or bundle ofconductive filaments/wires/fires or coated on to a tape or wovenmaterial. The microspheres (1) may be provided in a prearranged form ormay be sprayed or painted on shortly before use. Once sufficient thermalradiation and/or conduction is imparted to the microspheres they may beactivated at a selected temperature so as to accelerate and/or effectattachment in the initial state and debond in the expanded state. In thesecond phase with microspheres containing a blowing agent mixed with acuring activator in the instance of two surfaces having alreadyaccording to the present invention. Microspheres 1 can be seenprojecting above the surface thus providing an uneven or rough surface.There are gaps between the microspheres. However these gaps or voids arefilled once the microspheres have been expanded so that the surface willbecome more even and thus be able to be debonded. In FIG. 1B there isshown an electron microscope picture of a tangle of micro-wires andinter-dispersed microspheres are also visible. As described earlieraluminium or steel wires/filaments/strands, carbon microfibres, metalcoated glass fibres or micro-wires are embedded in the adhesivecomposition especially at the adhesive interface so as to create aFaraday cage. The micro-wires are dispersed in the adhesive to create atangle of electrical conductors. This tangle allows a great number ofsmall electrical rings to be formed in three dimensions all around themicrospheres which can be caused to expand at a maximum temperature.FIGS. 1C and 1D are electron microscope figures at higher powers ofmagnification.

In one embodiment of the invention, the microspheres (1) and micro-wires(2) can be attached to a continuous conductive filament or film or wireor fibre (4). Energy is supplied to the conductive filament (2) from anenergy source (3), the energy source may be provided in the form ofthermal energy or electrical power and transmitted to the microcapsulesby thermal radiation and/or thermal conduction. Thus the microcapsule donot receive energy directly from the energy source but rather via thepanel or component surface which is to be bonded, for example themicrospheres may be heated by thermal radiation and/or thermalconduction of the panel, directly targeted by an IR radiation lampfocused on the open/exposed surface. In a yet further embodiment of theinvention microcapsules (1) may be coated on to a mesh or bundle ofconductive filaments/wires/fires or coated on to a tape or wovenmaterial. The microspheres (1) may be provided in a prearranged form ormay be sprayed or painted on shortly before use. Once sufficient thermalradiation and/or conduction is imparted to the microspheres they may beactivated at a selected temperature so as to accelerate and/or effectattachment in the initial state and debond in the expanded state. In thesecond phase with microspheres containing a blowing agent mixed with acuring activator in the instance of two surfaces having already beenattached together by an adhesive may be made to expand and release theircontents at a different selected temperature and release an expandingagent such as a gas, an agent capable of sublimation, water, anexplosive agent containing an activator agent. The resultant expansioncauses a de-bonding or a faster bonding of the two attached surfaces.

In the instance of attaching a vehicle door skin (B) to a frame (A) asin FIG. 3, the microspheres may be provided in pre-defined paths alongthe perimeter of the article which it is desired to attach. Path (5) maybe in the form of a channel or groove into which the adhesivecomposition may be poured/sprayed or the microspheres may be providedalready attached in the form of a mesh or tape or strip which can beappropriately positioned on either or both of the skin (13) or frame(A). The door frame (A) and/or skin (13) is provided with a plurality ofconductive attachment means (6) and (7) respectively which can beconnected to an energy source. Once the energy source is activated andthe microspheres receive sufficient thermal radiation and/or conductionfor example from an IR lamp of the present invention, they may expandand release their contents to effect attachment at a selectedtemperature or to cause de-bonding at a different selected temperature.In this way and conveniently, adhesion of two surfaces and separation ofsame may be achieved without recourse to chemical or physical processesusing the same system and apparatus. Moreover and advantageously thesystem is controllable since the microspheres in the adhesive systemwill be selected according to the user's requirements of curing andbonding and debonding methods.

With reference to FIG. 4 there is shown a representation of a pluralityof different interfaces which are to be included within scope of the themethod of the present invention. For example the vehicle glass (11) tocleaner and/or primer (10), cleaner and/or primer (10) to adhesive (12),adhesive (12) to primer or paint (13) and primer or paint (13) to themetal part or similar (8).

It will be appreciated that the invention has wide application to maydifferent fields of technology where it is required to attach and detachtwo surfaces together for example and without limitations surfaces suchas plastics, metal, ceramic, fibreglass and/or composites thereof, andthat the examples in the present specification are not intended to limitthe scope of the application.

EXAMPLES

With reference to the table below, various samples of microspherecompositions have been tested. It will be appreciated that thetemperature activation ranges are dependent on the intended uses and assuch on which type of thermal energy is applicable forcuring/bonding/debonding. We have found that a typical composition fordirect automotive glazing should comprise about 3% microspheres in thecleaner and 5% in the primer for thermosetting adhesives and 5-10% forthermoplastic adhesives. For metal bonded surfaces the compositionshould be in the range 5-10% at their interface surfaces in the absenceof a primer. In the instance where the adhesive layer is of a comparablethickness to the diameter of the microsphere and can be activated onboth sides of the layer about 5% of microspheres is required. AverageActivation Diameter Range Activation Ref (μm) (C./Watts) Source Use 9030-50  80-100 C. IR; Air; UV; Curing adhesive Water compositions 9110-50 110-220 C. IR; Automotive, 500-1500 Electricity aircraft and Wattstrain glazing, car parts and panels 820a 10-30 150-180 C. IR; PlasticElectricity composite - glass layers 820b Approx 100-120 C. IR; Aircraftglazing 4 Electricity Floor covering 93-98 10-40 150-180 C. IR;Aluminium or Electricity other sheet metal- plastic layers  98-120  4-10100-120 C. IR; Hot Dispersion of air vapour nanoparticles on theirporous initial shell surface to avoid clustering in a mix with plasticbinders and solvents 551  4-10  40-80 C. Hot water Decorative paper, orair; IR; dentistry, UV; laser or medical surgery, concentrated sportsequipment light systems

1. A method of bonding and debonding two or more surfaces or supports orlayers of an adhesive system, the adhesive system comprising: (i) anadhesive composition at its bonded surface(s), the composition beingplaced between said surfaces or supports or layers, and the adhesivecomposition comprising an adhesive agent and/or a primer and/or acleaner at its interface and dispersed therein at least two sets ofthermoexpandable microspheres that are not simultaneously activatable;(ii) a first set of microspheres being associated with curing andbonding; and (iii) a second set of microspheres being associated withdebonding, wherein in order to debond the system a sufficient powerlevel of thermal radiation and/or thermal energy is provided whichconcentrates on the adhesive surfaces so as to expand the second set ofmicrospheres in the adhesive and/or a primer and/or a cleaner layers andso causes weakening of adhesive surface forces at the interface of saidlayers in the adhesive system.
 2. A method according to claim 1 whereinthe power level of thermal radiation and/ or thermal conduction and/orthermal energy which passes through the adhesive composition causes thecontents of the expanded microspheres to leach or migrate through theirporous shells into the matrix of the composition.
 3. A method accordingto either claim 1 wherein the microspheres encapsulate a blowing agentwhich acts as a carrier for the contents of the micro spheres.
 4. Anadhesive system comprising curing an adhesive composition and/orde-bonding the same adhesive at its bonded surface, the compositionbeing placed between two or more surfaces of supports or layers, and theadhesive composition comprising an adhesive and/or cleaner and/or primerat its interface and dispersed therein thermo-expandable microspheresthe system comprising the steps of: (i) activating a method of curingthe composition by providing a first power level of thermal radiationand/ or thermal conduction and/or thermal energy which passes throughthe adhesive composition so the contents of the expanded microspheresleach or migrate through their porous shells into the matrix of thecomposition and; (ii) de-bonding adhesive interfaces of the samesurfaces of supports or layers by providing a second power level ofthermal radiation and/ or thermal conduction and/or thermal energy whichconcentrates on the adhesive surfaces so as to expand the microspheresin the adhesive and/or cleaner and/or primer layers and so causeweakening of adhesive surface forces in the interface of the adhesivecomposition.
 5. A system according to claim 4 wherein step (i) isperformed after adhesive composition deposition and step (ii) isperformed days, weeks, months or years apart.
 6. A method or systemaccording to claim 1 wherein the microspheres comprise a co-polymericshell which encapsulates an expanding agent for the debondingmicrospheres and a curing agent or catalyst mixed with an expandingagent for step the curing microspheres.
 7. A method or system accordingto claim 6 wherein the expanding agent is selected from the groupcomprising an expandable gas, a volatile agent, a sublimation agent,water, an agent which attracts water or an explosive agent.
 8. A methodor system according to claim 2 wherein the microspheres encapsulatingthe curing agent have a larger cross sectional diameter than thoseencapsulating the expanding agent.
 9. A method or system according toany of claim 2 further comprising a curing activator.
 10. A method orsystem according to claim 9 wherein the curing activator is activated byan applied thermal energy or by its own energy.
 11. A method or systemaccording to claim 1 wherein the adhesive is polyurethane orpolyvinylchloride or an MS polymer or an epoxy resin.
 12. A method orsystem according to claim 1 wherein the microspheres are activated in atemperature range of about 45 to 220° C. for the debonding phase.
 13. Amethod or system according to claim 2 wherein the proportion ofmicrospheres encapsulating the curing agent are activated at a differenttemperature from those used in the debonding phase the temperaturedifference being between 20 to 100° C.
 14. A method or system accordingto claim 1 wherein the microspheres used in debonding microspheresencapsulating the expanding agent comprise about 3-5% weight in thecleaner and 5-10% weight in the primer at the adhesive interface.
 15. Amethod or system according to claim 2 wherein the microspheres used incuring encapsulating the curing agent or catalyst comprise about 2-3%weight of the composition.
 16. A method or system according to claim 1wherein the thermal radiation and/ or thermal conduction provided to themicrospheres is provided by a means comprising a source of IR or UVelectromagnetic radiation, or from a convection oven or from electricalmeans, a battery or a laser or from an ultrasonic source or from gas orfrom white light or microwaves or sonic waves.
 17. A method or systemaccording to claim 16 wherein in the instance of using IR radiation itis provided as a wavelength of about 800-1400 nm to 2000-6000 nm andconcentrates heating radiation on the microspheres in order to reachtheir activation expanding temperature in advance of the adhesive matrixdegradation temperature.
 18. A method or system according to claim 1wherein the thermoexpandable microspheres are provided embedded in orcoated on to a tape or mesh or film or attached to a wire or filament orfiber.
 19. A method or system according to claim 1 wherein themicrospheres are coated in a black material.
 20. A method or systemaccording to claim 1 wherein the microspheres are coated with orencapsulate a monomer and/or with nanoparticles dispersed in the porousinitial microsphere shell.
 21. A method or system according to claim 1wherein the microspheres act as a vehicle or transporter or carrier orbarrier or dispersing aid or aid to prevention of clustering ofparticles or nanoparticles or detergent or cleaning agent in a mixturecomprising a binder and solvent, the microspheres either encapsulating adesired agent or being coated with it.
 22. A method or system accordingto claim 1 wherein the microspheres are dispersed in an arrangement ofmicro-wires so as to form a polygonal arrangement.
 23. A method orsystem according to claim 22 wherein the micro-wires are about 100-200μin length.
 24. A method or system according to claim 23 wherein themicro-wires are about 2-20μ in diameter.
 25. A method or systemaccording to claim 22 wherein the composition comprises about 1-10%volume of micro-wires.
 26. A method or system according to claim 1wherein the thermoexpandable microspheres are attached to a contactsurface of one or more of the components which it is desired to attachand/or separate or on an internal surface of the components or at aninterface of the cleaner and/or primer of said components.
 27. A methodor system according to claim 1 wherein the adhesive compositioncomprising the microspheres is provided in a continuous or discontinuouspredefined or in spots in path or channel or groove or line orconcentric circles provided substantially around the periphery of one orboth of the contact surfaces of the items which it is desired to attachor detach.
 28. A method or system according to claim 1 wherein the depthand breadth or thickness and wideness of the adhesive composition may beuniform or may vary as required in areas of the surface(s) which need tobe attached or detached.
 29. A method of attaching or bonding two ormore surfaces together comprising: (i) applying an adhesive compositionaccording to claim to one or more of the contact surfaces of each or allitems which is to be bonded together; and (ii) supplying sufficientthermal radiation and/ or thermal conduction to the composition viacontact with one or more of the contact surfaces of each or all itemswhich is to be bonded together so as to cause a proportion of thethermoexpandable microspheres to expand and optionally to furtherrelease a curing agent into the composition during the bonding process.30. A method of detaching or debonding two or more surfaces that havebeen bonded together comprising, supplying sufficient thermal radiationand/ or thermal conduction to a surface having coated thereon orattached thereto the composition of claim 1, the thermal energy beingsupplied to one or more of the contact surfaces of each item which areto be detached/separated so as to cause the thermoexpandablemicrospheres to increase in volume and to become a pressure activator soas to debond the interfaces of the adhesion system.
 31. (canceled) 32.An apparatus for attaching or detaching two or more surfaces that havebeen bonded together comprising an IR emitting device comprising atleast one bulb, at least one lens and at least one reflecting mirrormutually arranged so that heat is directed or focused only at anadhesive interface or a path where the thermoexpandable microspheres arepresent.
 33. An apparatus according to claim 32 capable of emitting IRradiation in the range of about 800-1400 nm to 2000-6000 nm.
 34. Anapparatus according to claim 31 that is automated and operably linked toa computer program providing information to device sensors of anadhesive bonding path.
 35. An apparatus according to claim 32 mounted ona mobile unit so that it is free to follow a predefined adhesive bondingpath.
 36. An apparatus according to claim 35 capable of concentrating anIR beam at certain partial points of the surface which it is desired tobond or de-bond in different steps at command.
 37. An apparatusaccording to claim 36 that is pre-programmed to follow a specificbonding path in direction, width and breadth.
 38. A method of de-bondingan adhesive composition, the composition being present at an interfaceand being placed between two or more surfaces of vehicle glazing orvehicle panel(s) or part(s) the composition comprising an adhesive orcleaner and/or primer and thermoexpandable microspheres dispersedtherein the microspheres having a diameter of between 10-50 μm and anactivation temperature range of between 110-210 C° and encapsulating atleast one blowing agent the debonding being effected by exposing themicrospheres power level of thermal radiation and/or thermal energy thatresults in a temperature received by the microspheres in the range of110-210 C°.
 39. A method according to claim 38 further comprising curingthe adhesive composition prior to bebonding the curing comprisingproviding microspheres of 30-50 μm in diameter with an activationtemperature range of between 50-100 C° the microspheres encapsulating acuring agent and/or catalyst and/or activator and effecting curing byexposing the microspheres power level of thermal radiation and/orthermal energy that results in a temperature received by themicrospheres in the range of 50-100 C°.
 40. A method of curing anadhesive and de-bonding the same adhesive from automotive glazing orpanels or parts comprising applying a composition comprising an adhesiveand thermoexpandable microspheres dispersed therein, a first set ofmicrospheres having a diameter of between 30-50 μm and an activationtemperature range of between 50-100 C° and a second set of microsphereshaving a diameter of between 10-50 μm and an activation temperaturerange of between 110-210 C° the second set of microspheres being presentat an interface of the adhesive or cleaner and/or primer, thecomposition being placed between two or more surfaces of the glazing orpanel or part(s) and: (i) activating curing of the composition byexposing it to a first power level of thermal radiation and/or thermalenergy that results in a temperature received by the microspheres in therange of 50-100 C°; and (ii) de-bonding the adhesive system at itsinterfaces by exposing it to a first power level of thermal radiationand/or thermal energy that results in a temperature received by themicrospheres in the range of 110-210 C°.
 41. (canceled)
 42. A methodaccording to claim 38 for the removal of vehicle glazing or panels orparts in an end of vehicle life process.
 43. A method of detaching ordebonding two or more surfaces that have been bonded togethercomprising, supplying sufficient thermal radiation and/ or thermalconduction to a surface having coated thereon or attached thereto thecomposition of claim 4, the thermal energy being supplied to one or moreof the contact surfaces of each item which are to be detached/separatedso as to cause the thermoexpandable microspheres to increase in volumeand to become a pressure activator so as to debond the interfaces of theadhesion system.